Grammar school appeal

My daughter is in year 12. She's been struggling with one of her subjects, Law, and has recently made the momentous decision to not sit her AS level. The school wanted her to leave immediately but after pressure from myself and her other subject teachers she is being allowed to sit her other 2 AS levels.The school do not want her to return next year as she will only be taking 2 A levels nor will they let her resit the year taking a different subject.Do we have any grounds for appeal?